Magnetic alloy



INDUCT/UN PERMEAB/L/TY.

Y. MATSUYAMA ET AL 16,401

MAGNETIC ALLOY Filed June 2, 1937 FIELD STRENGTH H F/ELD smg/var/ H Inventovs:

YOShUi Matsuyarna, Shukichi Kuno, Shigeji Nasu,

Their Attorney.

Patented May 3, 1938 UNITED STATES PATENT OFFICE Nasu, Tokyo,

Japan,

assignors to General Electric Company, a corporation of New York Application June 2, 1937, Serial No. 146,012 In Japan September 11, 1936 1 Claim.

The present invention relates to alloys and more particularly to magnetic alloys.

It is one of the objects-of the present invention to provide a magnetic material which has a small hysteresis loss and a high specific electric resistance at extremely high initial magnetic permeability and which also, at low magnetizing fields, has a relatively high magnetic induction and a relatively small iron loss.

The novel features which are characteristic of our invention are set forth with particularity in the appended claim. Our invention, however, will best be understood from reference to the following specification when considered in connection with the accompanying drawing in which Fig. 1

is a curve showing. the relation between field strength and induction, and Fig. 2 is a curve showing the relation between field strength and permeability.

In carrying out the present invention, we employ an alloy containing about 50% to 95% nickel,

about 5% to 50% iron, about 1% to 10% molybdenum, about 1% to 10% chromium, 0 to 3% manganese, from 0 to 5% copper and 0 to 5% tin. The alloy is characterized by its high initial permeability, its relatively low residual magnetism and hysteresis loss and its high specific electric resistance. As indicated in Fig. 2, it is particularly noticeable in the present alloy that the difference between maximum permeability and initial magnetic permeability is quite small, 1. e.

the variation of magnetic permeability due to increase of the magnetizing field is relatively small. In these aspects the present alloy is far superior to alloys now in use.

Heat treatments of magnetic alloys usually are complicated, but necessary to produce the highest magnetic qualities. In the present case the alloy is heated at about 1000" C. for about thirty minutes and then cooled in the furnace. The

simple heat treatment which applicants employ is highly advantageous'in producing a magnetic material of uniform superior quality.

Applicants preferred alloyconsists of about.

4.5 80.5% nickel, 13.5% iron, 3% molybdenum, 2%

chromium, and 1% tin by weight. The mixed ingredients preferably are melted in a high frequency inductance furnace and deoxidized by manganese, silicon, or calcium, or other suitable means.

The alloy is usually cast into bars 8 mm. in 5 diameter and then drawn into wire about 1.55 mm. in diameter. The characteristics of the metal may be tested by employing a piece of wire about 30 centimeters long. The results obtained therefrom are far better than those ob- 10 tained from alloys of this type heretofore employed.

The following illustrate some 01 the characteristics of the material: Initial permeability U0 22,500 15 Maximum permeability U max 37,000 Magnetizing field U max 0.1 Residual magnetism when B max.=

6000 500 Coercive force when Bmax.=6000 0.01 20 Specific resistance 9x10 ohms/ccm '10 The hysteresis loss at 8 max. 6000 is a little less than 20 per cycle,'per cm. A small difierence between initial permeability and maxl- 2 mum permeability means a small change in permeability due to the change in the magnetizing field. The specific electric resistance of the present alloy is about 0.000070 ohm per cm at room temperature of about 20 C.

The present alloy is particularly well adapted for use in radio transformer cores, electric meters, loading coils for submarine cables, field interrupters, relays and other electromagnetic materials. Less than 2% of cobalt and small quantities of impurities such as magnesium, aluminum, silica and calcium do not affect the magnetic properties of the alloy.

What we claim as new and desire to secure by Letters Patent 01 the United States is:

A magnetic alloy composed oi the following ingredients: about 80.5% nickel, 13.5% iron, 3% molybdenum, 2% chromium, and 1% tin.

YOSHIJI MATSUYAMA. SI-IUHCHI KUNO. BHIGEJI NASU. 

